• 한국해양환경ㆍ에너지학회지
• /
• 제4권4호
• /
• pp.42-50
• /
• 2001

본 논문에서는 수출입컨테이너 화물의 육상운송에서 연안운송으로의 전환을 이용한 CO₂가스 및 배기가스 배출량 삭감이 제안되어진다. 먼저 국내의 CO₂가스 배출량, 배기가스 배출량, 수출입컨테이너화물의 물동량 등에 대하여 간단히 살펴본다. 또한 경인지역과 부산항사이의 수출입컨테이너화물 수송에 대하여 육상운송에서 연안운송으로의 변환에 의한 CO₂가스 및 배기가스 배출량 삭감효과에 대하여 고찰한다. 마지막으로 연안운송의 분담율 변화와 320TEU 소형컨테이너선 이용에 따른 NOx가스 배출량 변화를 고찰한다. 본 연구의 결과 육상운송에서 연안운송으로의 전환이 CO₂가스 및 배기가스 배출량 삭감에 효과적인 것을 확인하였다.

• Journal of Korean Society for Atmospheric Environment
• /
• 제20권E2호
• /
• pp.69-75
• /
• 2004

In this study, thin film gas sensor based on tin oxide was fabricated to examine its characteristics. Target gas is acetonitrile ($CH_3$CN) which is a blood simulant for the chemical warfare agent. Sensing materials are SnO$_2$ SnO$_2$/Pt, and Sn/Pt with thickness from 1000 to 3000 $\AA$. The sensor consists of a sensing electrode with inter-digit (IDT) type in front side and a heater in rear side. Resistance changes of sensing materials are monitored on real time basis using a data acquisition board with a 12-bit analog to digital converter. Sensitivities are measured at different operating temperatures also with different gas concentrations and film thickness. The high sensitivity is obtained for Sn (3000 $\AA$)/Pt (30 $\AA$) at 30$0^{\circ}C$ for 3 ppm. Response and recovery times were about 40 and 160 s, respectively. Repetition measurements showed very good results with $\pm$3% in full scale range.

• 한국물환경학회지
• /
• 제34권6호
• /
• pp.642-649
• /
• 2018

The effect of gas sparging on sonochemical oxidation was investigated in a 300 kHz sonoreactor under various liquid height/volume conditions ($5{\sim}30{\lambda}$, 3.4 ~ 9.0 L), determined by the wavelength of the applied frequency. The electrical input power was maintained constant for all cases . Sonochemical activity drastically decreased from $15{\lambda}$ and the liquid height of $10{\lambda}$ was suggested as the optimal height for 300 kHz without gas sparging. In our previous research, the sonochemical activity observed was five-times higher when air sparging was applied for 36 kHz. On the other hand, no enhancement was obtained at 10, 15, 25 and $30{\lambda}$ using air sparging (1, 3, and 6 L/min) for 300 kHz in this study $20{\lambda}$ and optimization of gas sparging was conducted at $20{\lambda}$ using various gases including air, Ar, $O_2$, $N_2$, and mixtures of Ar and $O_2$. It was found that gas sparging using pure Ar or pure $O_2$ resulted in lower sonochemical activity compared to that of air sparging due to the imbalance between the intensity of cavitation phenomena and the generation of oxidizing radical species. Consequently, the gas mixture of $Ar:O_2$ = 80 % : 20 % (DO saturation ${\approx}100%$) was suggested as an optimal gas sparging condition.

• 환경영향평가
• /
• 제22권6호
• /
• pp.639-648
• /
• 2013

Unconventional natural gas resources are now estimated to be as large as conventional resources. Unconventional natural gas has became an increasingly important source of energy in the world since the start of this century. The factors that drive natural gas demand and supply point more and more to a future in which natural gas plays greater role in the global energy mix. The expansion of using natural gas will be expected in Korea. This research aims to analyze environmental impacts of expansion of unconventional natural gas. This research was carried out for comparative analysis between global energy mix and Korea energy mix, and developed a case that reflect the changed energy mix due to the expansion of unconventional natural gas in Korea. Also this research evaluate the production of air pollutants and the cost of the damage in power generation sector. The results of this research can be summarized as that natural gas portion of future global energy mix (about 25%) is greater than Korea energy mix (about 12%). This research developed a case that replace 10% energy of power generation sector to natural gas in the 6th demand supply program, reflecting the changed energy mix due to the expansion of natural gas use. In that case, air pollutants would be reduced gradually through 2015 to 2027. In detail, carbon dioxide reduces 22 million tons and environmental damage cost reduces 4500 billion won by 2027.

• 천문학논총
• /
• 제30권2호
• /
• pp.491-494
• /
• 2015

We present 12CO (2-1) data for four spiral galaxies (NGC 4330, NGC 4402, NGC 4522, NGC 4569) in the Virgo cluster that are undergoing different ram pressure stages. The goal is to probe the detailed molecular gas properties under strong intra-cluster medium (ICM) pressure using high-resolution millimeter data taken with the Submillimeter Array (SMA). Combining this with Institut de RadioAstronomie $Millim{\acute{e}}trique$ (IRAM) data, we also study spatially resolved temperature and density distributions of the molecular gas. Comparing with multi-wavelength data (optical, $H\small{I}$, UV, $H{\alpha}$), we discuss how molecular gas properties and star formation activity change when a galaxy experiences $H\small{I}$ stripping. This study suggests that ICM pressure can modify the physical and chemical properties of the molecular gas significantly even if stripping does not take place. We discuss how this affects the star formation rate and galaxy evolution in the cluster environment.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2012년도 춘계학술발표회 논문집
• /
• pp.338-339
• /
• 2012

This study examined the friction and wear behavior of diamond-like carbon (DLC) films deposited from a radio frequency glow discharge using a hydrogen diluted benzene gas mixture. The DLC films were deposited on Si (100) and polished stainless steel substrates by r.f.-PACVD at hydrogen to benzene ratios, or the hydrogen dilution ratio, ranging from 0 to 2.0. The wear test was carried out in both ambient and aqueous environments using a home-made ball-on-disk type wear rig. The stability of the DLC coating in an aqueous environment was improved by diluting the benzene precursor gas with hydrogen, suggesting that hydrogen dilution during the deposition of DLC films suppress the initiation of defects in the film and improved the adhesion of the coating to the interface.

• 한국가스학회지
• /
• 제18권5호
• /
• pp.72-77
• /
• 2014

우리나라는 영구 동토지역이 존재하지 않는 기후적 특성으로 인해 건설수요가 없었지만, 최근 지구 온난화 현상으로 인하여 화석연료의 사용 보다 극한지 지역의 에너지 확보가 대두되고 있다. 이에 극한지 지역에서 사용하고 있지 못한 에너지 자원의 관심이 증가함에 따라 알레스카 및 시베리아의 천연가스의 개발이 필요성이 증대하고 있다. 이에 따라 극한지 지역에서 필요한 배관 설계 기술은 현재 국내에서 사용되고 있는 천연가스와 전혀 다른 환경에서 운용될 것이 예상되며, 이에 따른 설계 기초 자료가 필요하다. 그러므로 극한지 환경에서의 토양 물성에 따라 배관에 미치는 영향 분석이 필요하다. 현재 배관의 설계는 응력 기반으로 설계되어있지만 추후 변위를 기초하는 설계법이 필요하며, 우선적으로 이를 위한 영구동토층 및 활동층에 대한 영향 분석이 필요하다. 본 연구에서는 유한요소해석을 이용한 Thermal elasto-plastic analysis를 통해 활동층의 영향에 따른 배관의 응력 및 변위 측정을 알아보고자 한다.

• 한국물환경학회지
• /
• 제20권1호
• /
• pp.72-77
• /
• 2004

Laboratory studies were carried out to find out the characteristics of humic acid treatment by activated carbon and ionized gas, In order to increase oxidation power of ionized gas for treating organic matter, we used granular activated carbon. By using $UV_{254}$, easy analysis method, we calculated humic acid concentration and $SCOD_{cr}$ concentration. For an initial concentration of humic acid, 10, 50 and 100ppm, the reaction rate constant by $UV_{254}$ was $8.98{\times}10^{-3}$/min, $5.62{\times}10^{-3}$/min and $4.8{\times}10^{-3}$/min respectively due to the same flow rate of ionized gas. When we added activated carbon to the ionized gas for humic acid treatment, the reaction rate constant increased in 4.13, 3.65 and 3.15 times. So, by using activated carbon in treating humic acid by ionized gas, oxidation power of organic matter by ionized gas was increased. The hydrophobic fraction constitutes 98% of organic matter for humic acid at the beginning. After the treatment using ionized gas for humic acid, the hydrophobic fraction decreased by 63~65% and the hydrophilic one increased by 35~37%. So, it was proved that the treatment increased the hydrophilic fraction in organic matter.

• 전자공학회논문지
• /
• 제49권9호
• /
• pp.314-321
• /
• 2012

축산생육환경에서 다양한 경로로부터 발생하는 유해가스는 가축 및 농가작업자에게 직/간접 적으로 영향을 미칠 수 있으며, 점차적인 사육조밀화와 동절기 밀폐환경에 장기간 노출 시 치명적일 수 있다. 본 논문에서는 가축분뇨로부터 발생하는 암모니아, 황화수소, 휘발성유기화합물 가스 등을 모니터링하기 위해 무선가스센서노드와 퍼지 최소-최대 신경회로망을 이용한 가스인식 소프트웨어로 이루어진 가스측정시스템을 제안한다. 제안한 시스템의 성능을 평가하기 위해 가스측정실험환경을 구축하여 제작한 무선가스센서노드로 가스측정실험을 수행하고, 개발한 가스인식 소프트웨어로 대상가스 분류시험을 통해 성능을 입증한다.

• 한국가스학회지
• /
• 제18권1호
• /
• pp.8-16
• /
• 2014

본 연구에서는 국내에서 발생한 가스사고를 분석하여 가스사고의 건수예측모델에 대하여 제시하였다. 가스사고 건수를 예측하기 위하여 단순이동평균법(3,4,5기간), 가중이동평균법 및 지수평활법을 적용해 본 결과, 4기간 이동평균법과 가중이동평균법에 의한 모델의 평균오차제곱합이 44.4와 43으로 가장 정확성이 높은 것으로 나타났다. 가스사고 발생건수 예측시스템을 개발함으로서 가스사고 예방활동에 적극 활용할 수 있을 것이다.